After the collapse of the Sumerian
civilization, the people were reunited in 1700BC by King
Hammurabi
of Babylon (1792-1750 BC), and the country flourished under the name
of Babylonia. Babylonian rule

encompassed a huge area covering most of the Tigris-Euphrates river
valley from Sumer and the Arabian Gulf (Persian Gulf). He extended his
empire northward through the Tigris and Euphrates River valleys and
westward to the coast of the Mediterranean Sea. After consolidating his
gains under a central government at Babylon, he devoted his energies to
protecting his frontiers and fostering the internal prosperity of the
Empire. Hammurabi's dynasty, otherwise referred to as the First Dynasty
of Babylon, ruled for about 200 years, until 1530 BC. Under the reign of
this dynasty, Babylonia entered into a period of extreme prosperity and
relative peace.

Throughout his long reign Hammurabi
personally supervised navigation, irrigation, agriculture, tax
collection, and the erection of many temples and other buildings.
Although he was a successful military leader and administrator,
Hammurabi is primarily remembered for his codification of the laws
governing Babylonian life. Under Hammurabi the two cultures which
compose Mesopotamian civilization [the Assyrians and the
Babylonians] achieve complete and harmonious fusion.

Hammurabi was a king and a great lawgiver of
the Old Babylonian (Amorite) Dynasty. His law code was produced in the
second year of his reign. Many new legal concepts were introduced by the
Babylonians, and many have been adopted by other civilizations. These
concepts include: Legal protection should be provided to lower classes;
The state is the authority responsible for enforcing the law; Social
justice should be guaranteed; The punishment should fit the crime.

Hammurabi Code, ("An eye for an eye, a
tooth for a tooth.") is still quoted today attests to its importance, is
a collection of the laws and edicts of the Babylonian king Hammurabi,
and is considered the earliest legal comprehensive code known in
history. A copy of the code is engraved on a block of black diorite
nearly 2.4 m (8 ft) high. A team of French archaeologists at Susa, Iraq,
formerly ancient Elam unearthed this block, during the winter of 1901-2.
The block, broken in three pieces, has been restored and is now in the
Louvre Museum in Paris.

On Hammurabi's death, however, a tribe known as
the Cassites (Kassites) began to attack Babylonia as early as the period
when Hammurabi's son ruled the empire. Over the centuries, Babylonia was
weakened by the Cassites. Finally, around 1530 BC (given in some sources
as 1570 or 1595 BC), a Cassite Dynasty was set up in Babylonia. The
Mitanni, another culture, were meanwhile building their own powerful
empire. They were having a "considerable, if temporary importance"--they
were very powerful but were around for only about 150 years. Still, the
Mitanni were one of the major empires of this area in this time period,
and they came to almost completely control and subjugate the Assyrians
(who were located directly to the east of Mitanni and to the northwest
of Cassite Babylonia).

The Assyrians, after they finally broke free of
the Mitanni (who were having political troubles of their own), were the
next major power to assert themselves on Babylonia. After defeating and
virtually annexing Mitanni, the Assyrians, reasserted themselves on
Babylonia. They weakened Babylonia so much that the Cassite Dynasty fell
from power; the Assyrians virtually came to control Babylonia, until
revolts in turn deposed them and set up a new dynasty, known as the
Second Dynasty of Isin. Nebuchadnezzar the First, of this Dynasty, added
a good deal of land to Babylonia and eventually came to attack Assyria,
the land was under Assyrian rule for about two centuries.

The Assyrian culture showed a dramatic growth
in science and mathematics, among the great mathematical inventions of
the Assyrians was the division of the circle into 360 degrees and were
among the first to invent longitude and latitude in geographical
navigation. They also developed a sophisticated medical science, which
greatly influenced medical science as far away as Greece. In the 6th
century BC (586 B.C.), Nebuchadnezzar conquered Judea (Judah), destroyed
Jerusalem; Solomon's Temple was also destroyed; Nebuchadnezzar carried
away an estimated 15,000 captives, and sent most of its population into
exile in Babylonia.

It was not until the reign of Naboplashar
(625-605 BC) of the Neo-Babylonian dynasty that the Mesopotamian
civilization reached its ultimate distinction. His son, Nebuchadnezzar
II (604-562 BC) is credited for building the legendary Hanging Gardens,
one of the seven wonders of the ancient world. It is said that the
Gardens were built by Nebuchadnezzar to please his wife or concubine,
Amyitis, who had been "brought up in Media and had a passion for
mountain surroundings". He did this because his wife had lived in the
mountains and she was homesick on the flat plains of Babylon. He planted
a large amount of brightly colored tropical plants on the roof of the
palace.

The gardens were completed around 600 BC. The
Hanging Gardens were built on top of stone arches 23 meters above ground
and watered from the Euphrates by a complicated mechanical system. It
was Nebuchadnezzar II who restored Mesopotamia to its former Babylonian
glory and made Babylon the most famous city of the ancient world

The Hanging Gardens on the east bank of
the River Euphrates, about 50-km south of Baghdad, Iraq, used to be
considered as one of the Seven Wonders of the World. "Has plants
cultivated above ground level, and the roots of the trees are embedded
in an upper terrace rather than in the earth. The whole mass is
supported on stone columns... Streams of water emerging from elevated
sources flow down sloping channels... These waters irrigate the whole
garden saturating the roots of plants and keeping the whole area moist.
Hence the grass is permanently green and the leaves of trees grow firmly
attached to supple branches... This is a work of art of royal luxury and
its most striking feature is that the labor of cultivation is suspended
above the heads of the spectators."

In 626 BC, the Chaldeans helped Nabopolassar to
take power in Babylonia. At that time, Assyria was under considerable
pressure from an Iranian people, the Medes (from Media). Nabo-polassar
allied Babylonia with the Medes. Assyria could not withstand this added
pressure, and in 612 BC, Nineveh, the capital of Assyria, fell. The
entire city, once a great capital of a great empire, was burned and
sacked.